WordPress at a glance
filter is not described

get_comments_number filter-hook . WP 1.5.0

Filters the returned comment count for a post.

Usage

add_filter( 'get_comments_number', 'filter_function_name_2785', 10, 2 );
function filter_function_name_2785( $count, $post_id ){
	// filter...

	return $count;
}
$count(string/int)
A string representing the number of comments a post has, otherwise 0.
$post_id(int)
Post ID.

Where the hook is called

get_comments_number()
get_comments_number
wp-includes/comment-template.php 859
return apply_filters( 'get_comments_number', $count, $post_id );

Where the hook is used (in WP core)

Does not used.